Apparatus for breaking coal



June 10, 1930. w. K. LIGGETT 1,763,165

APPARATUS FOR BREAKING COAL Filed Dec. 4, 1925 2 Sheets-Sheet 1 h "'JHfi'IO, 1930. w. K. LIGGETT APPARATUS FOR BREAKING COAL Filed Dec. 19252 Sheets-Sheet 2 III/IIIIIIIIIIIIIII mm; W

with slack.

Patented June 10, 1930 UNITED STATES PATENT OFFICE WILLIAM K. LIGGETT,OF COLUMBUS, OHIO, ASSIGNOR TO THE JEFFREY MANUFAC- TURING COMPANY, OFCOLUMBUS, OHIO, A CORPORATION OF OHIO APPARATUS FOR BREAKING GOALApplication filed December 4, 1923.

This invention relates to new and useful methods of and apparatus forreducing material from relatively large to smaller pieces.

As an illustrative example, I shall herein describe my improved methodand apparatus in connection with the reduction of run of mine coal, socalled for the reason that as the coal comes from the mine, it is madeup of relatively large lumps of di'lferent'sizes mixed In reducing thismaterial for use in mechanical stoker grates, it is desirable to bringit to a uniform and predetermined size without undue pulverization, itbeing desirable to avoid, so far as possible, increasing the amount ofslack.

It will be understood that this disclosure is simply illustrative and inno sense restrictive of my invention, which is adapted to the reductionof material other than that herein specifically disclosed.

The means by which I attain this object are fully set forth in thefollowing specification, and illustrated in the accompanying drawings,which show one physical embodiment of my invention, and in which Fig. 1is a side elevation of a machine embodying my invention.

Fig. 2 is a sectional view taken on substantially the line IIII of Fig.1.

Fig. 8 is a transverse sectional view taken on substantially the lineIIIIII of Fig. 2.

Fig. 4 is a fragmentary sectional view taken on substantially the lineIVIV of Fig. 3.

Referring to the drawings by numerals, like numbers indicating likeparts in the several figures, it will be seen that, as here shown, myimproved machine consists of a reducing element which may, of course,take various forms, but in this illustration of the invention, is in theform of a skeleton rotor adapted to revolve within a casing, itbeingshown in the present instance as revolvingabout a horizontal axis,which casing is adapted to confine the material. The casing comprisesthe main supporting frame 1 and the housing 2 which are joined together,as here shown, along the horizontal central plane of the rotor, althoughvariations of this arrangement may be made. The main frame 1 has the endwalls 3 and the side walls 4, prefer- Serial No. 678,456.

ably, though not necessarily, formed of a single casting. These wallsmay be provided along their lower edges with flanges 5 adapted to restupon and be attached to any suitable foundations, and their upper edgesare flanged, as at 6, to permit the housing 2 to be bolted thereto.

At the ends of the main frame 1 are journal bearings 7 which may be ofany suitable type, and are designed to support the rotary element of themachine. J ournaled in the bearings 7, and in the embodiment of theinvention herein disclosed projecting at both ends beyond said bearings,is a shaft 8, to one end of which is attached a pulley 9 by which therotor may be connected through a suitable belt with any convenientsource of power.

Obviously drive mechanisms of other types may be used, if desired.

Mounted upon the shaft 8, and here shown in spaced relation to oneanother, are a plurality of discs 10 which are secured to the shaft 8 inany preferred manner, as by the key 11, to revolve therewith. Disposedlongitudinally of the shaft 8 and supported in suitable apertures of thediscs 10 are a plurality of rods 12 upon which arms designed to engageand reduce the material are supported. The arms are preferably formed ofcastings of a refractory alloy of iron, fashioned to provide threeradial projections 13, 14 and 15, preferably equally spaced andextending from a common center, each of said arms being pierced by anaperture 16 adapted to receive one of the rods 12. lVhen in operativeposition upon the rotor two of the arms 14 and 15, project into thespace between two of the discs 10 in such position that two of the rods12 may extend through their apertures 16 to rigidly hold the third arm13 extending radially be yond the periphery of the discs 10. The arms13, 14 and 15 are preferably symmetrical, as shown, so that when one endor radial extension becomes worn, the three armed plate may 9 be turnedand a new end brought into service. As shown in Figs. 3 and 4, theradially pro jecting arms 18 are preferably arranged in six longitudinalrows, equally spaced circumferentially of the rotor, but only two arm Vor housing 2.

members are positioned in the space between any two discs. The arms ineach space are advanced one longitudinal row beyond the arm in the nextpreceding space, thus producing spiral lines of arms extending aroundthe rotor from end to end thereof, and giving, when the machine is inoperation, a continuous and progressive action on the material underreduction, and generating a substantially continuous surface on whichthe material will be supported.

\Vith this arrangement of arms there will be provided, when the rotor isin motion, a substantially continuous surface, the circumference ofwhich is conventionally indicated by the dotted line in Fig. 3. \Vhenthe rotor is at speed the continuous surface thus generated willsubstantially support or float thematerial under reduction and hold itin suspen sion and in mobile condition in the chamber Reduction of thematerial will be effected by the action of the arms 13 as they revolveagainst the surface of the mass, and the action being a steady anduniform one, a uniform product will result. The relation of the rotorwith its engaging elements 13 to the chamber or housing 2 is such thatthe material under treatment is reduced princi pally by the action ofthe reducing elements as they strike the mass, as distinguished from itsbeing dragged down into and crushed be tween rotor and opposedabutments, as in the usual type of crushing machine.

In the arrangement here shown to illustrate my invention, the housing 2is above and encloses substantially the upper half of the rotor,although it is conceivable and entirely possible that the housing mightbe otherwise disposed relative to the rotor, and contains the reducingchamber 17 in which the prin cipal reducing operation occurs. Thehousing 2 has the end walls 18, bolted to the flanges 6 of the baseframe, and joined together at the rearward side of the breaking chamberby the casing plate 19 and hopper plate 20. At the forward side of thehousing 2 the end walls 18 are held by the draw bolt 21, from which issuspended a plate 22 to close the forward side of the reduction chamber.A goose neck bracket 23, attached to the lower side of the plate 22, isengaged by the rotary adjusting screw 2* threaded into a suitable nut 25attached to the main frame. Manipulation of the screw 24 effects theadjustment of thelower edge of the plate 22 towards or from the rotor.here hard material is being reduced, and the interior surfaces of thehousing 2 are exposed to the abrasive action of flying fragments comingfrom the mobile mass held up in the chamber by the action of the rotor,they are protected by suitable lining plates formed of any suitablematerial, as, for example, a refractory alloy of iron, and the plate 22is protected by the lining 26 having, at its lower edge, a shelf 27. Theupper surface of th1s shelf 27 extends along lines which aresubstantially radial of the rotor, to points in close proximity to thepath of rotation of the ends of the arms 13, and forms an abutment whichengages advancing material and acts to prevent the passage of oversizefragments downward from the breaking chamber into the lower part of thecasing under the action of the rotor and its reducing arms 13, and soensures a floating condition of the material upon and above the rotor.

Adjustment of this abutment 27 through the devices just describedrelative to the path of travel of the reducing elements 13, in this casecarried by the revolving rotor 10, enables me to vary, to a considerableextent. the size of the output of the machine. A close adjustment of theabutment 27 to the path of travel of the reducing elements 13 willresult in fine material, and adjustment away from the path of travelwill result in coarser material. This is due to the fact that therelation of abutment and reducing elements determines, to a largedegree, the size of the material which can flow downward to the screenbelow, a course adjustment permitting larger pieces than a fineadjustment. This arrangement, together with the screen through which thematerial ultimately passes, and which will now be described, enables meto control the output of the machine, so far as size is concerned.

The casing is closed beneath the rotor by a semicylindrical screen,concentric with and in close proximity to the path of travel of the endsof the arms 13, and this screen is adapted to permit fine material topass out of the casing and to retain such small percentage of fragmentsas may have passed down through the rotor and are too large to passthrough the screen, within the influence of the arms 13. This screen maytake various forms, but preferably is formed of a series oflongitudinally disposed bars 28, the spacing of which determines thesize of the maximum fragments of the product. The screen thus formed maybe divided into two sections, and in such construction, the forwardsection 29 will be rigidly supported by flag ges 30 cast integral withthe main frame, and the rearward section 31 supported by a frame 32hinged upon a longitudinally extending shaft 33, and held in workingposition by the toggle levers 34. The toggle levers 34 are fixed to ashaft 35 journaled in apertures in the casing walls, and a rocker armattached to the shaft 35 may be provided to actuate it. By rotatingshaft 35 the screen section 31 may be dropped away from the rotor topermit the removal of unbreakable objects, which may accidentally findtheir way into the machine and get below the rotor, and a counter-weight37 attached to the rocker arm 36 serves to return the screen section toand maintain it in operative position.

It will be observed that with the construction here shown the rotor iscompletely enclosed or boxed by the closely fitting casing and screen,leaving exposed substantially the upper surface of the rotor surmountedby the hopper. This gives a definite area of material exposed to theaction of the rotor, and the contents of the hopper, under the action ofgravity, rest and float upon the rotor and are subjected to rotor actionon the underside of the mass. The plate 22,,and its lining 26, andabutment 27, receives and resists any forward impulse imparted to themass by the rotor, and the close relation of the abutment 2'? to therotor prevents any tendency of oversize material to work downward intothe rotor casin To attain maximum efficiency; maintain constant rotorspeed, and prevent choking of the machine, the material which is to bereduced should be fed into the reducing chamberin asu'bstantiallycontinuous and reasonably uniform stream. This may be accomplished byany preferred mechanism suitable for the purpose. For purposes ofillustration in this embodiment of my invention, I have shown in thedrawings a feeding device comprising a hopper 38 positioned above themachine, and terminating downwardly in a substantially semi-cylindricalchamber having the side Walls 39 and the revolving circular bottom plate40. The bottom plate 40, as here shown, is mounted concentrically uponthe end of a vertical shaft 41 to revolve with it. Obviously the plate40 might be actuated by other means. The shaft 41 is supported inbearings 42 of the feeder frame 43 which is bolted to the main frame 1of the machine. A worm wheel 44 attached to the shaft 41 is engaged by aWorm 45 mounted upon a horizontal shaft 46 which is driven through apulley 47 and belt 48 from the rotor shaft 8. The feeder plate40preferably projeots slightly beyond the upper edge of the casing plate20, and a scraper 49 attached to the side wall 39 cooperates with thefeeder plate 40 to transfer coal from the hopper 38 into the breakingchamber as said feeder plate revolves. Shield plates 50 and 51 attachedto the plate 39 of the hopper are arranged to intercept flying fragmentsof coal projected from the reducing chamber, and a slide plate 52 isarranged beneath the hopper to permit adjustment of the feed openingfrom the hopper to control the rate of feeding.

In the reduction of coal, which is ordinarily supplied to steam powerplants in the form commonly called run of mine and contains aconsiderable proportion of slack mixed with lumps of various sizes, amachine designed to and capable of preparing fuel for antomaticmechanical stokers should be adapted to break the lumps into uniformfragments of a size sufficient to insure the proper flow of air throughthe fuel bed, while small enough to be completely burned before beingdischarged into the ash pit, and such reduction shouldbe accomplishedwithout materially increasingthe proportion of slack which is normallypresent.

In the illustration of my method and apparatus here given, and undernormal operating conditions, the rotor will be driven at a speed to bedetermined by the character of the material under reduction. That speedmust be sufficiently rapid to reduce thematerial without being highenough to bring about pulverization, and produce an excessive amount offines. For example, to reduce the larger fragments of the average run ofmine coal without increasing the slack, the rotor would be givenaperipheral speed of approximately eighteen hundred (1800) feet perminute; The maximum size of the reduced output would, of course, becontrolled by adjustment of the abutment 27 to the path of the reducingelements 13, as heretofore pointed out, and also by the spacing of thegrate bars 28.

To produce half-inch stoker coal, the grate bars would be spacedone-half an inch apart, and the abutment approximately adjusted. Forother sizes, the spacings of the bars and the abutment'would be alteredto meet the conditions. K

In coal reducing operations, .run of mine coal, as above SDGClfiGCl,falls from the feeder plate 40 directly upon the ends of the arms.13

of the rotor, which arms, by virtue of their disposition and rotation,generate a substantially continuous supporting surface upon which thelarger fragments of coal will float or be suspended. These floatinglumps of coal roll upon the supporting surfaces of the rotor, and areprevented from traveling beyond and escaping from the breaking chamber17 by the abutment 27. By this rolling and agitating action the coal inthe breaking chamber is keptin a state of violent agitation, resultingin its rapid disintegration. Due to the spacing of the arms 13 bothlongitudinally and circumferentially of the rotor, the smaller fragmentsof coal fall between s a1 d arms, and, as the low speed rotationeliminates high centrifugal force, this fine material is permitted toflow through the skeleton rotor and the screen 29 so that the machineclears rapidly and output is higln VJhile I have shown and described thereduction of coal in this disclosure of my method and apparatus, it is,of course, adapted to the reduction of other materials, and theconstruction may be varied in many particulars. For example, instead ofthe grate bars 28, a plate having perforations of proper size to limitthe maximum fragments of material might be used. In fact, equivalentdevices for carrying out the method embodying the principles here setforth may be substituted for those disclosed and still be within therange of my development.

From the foregoing description, it will be seen that a method andapparatus is provided for the reduction of materials of various kinds,and particularly for those materials, such as coal, in which largefragments and fine materials are mixed, and from which it is desired tosecure a uniform product, the maximum fragments of which shall be ofpredetermined size, and which product shall not have any materialproportion of fine material added thereto.

Following my method and using my machine, as herein set forth, it willbe seen thatthe mass of material which is fed in a uniform andcontinuous stream into the hopper is maintained during reduction in asuspended and mobile condition by the action of the continuouslyrevolving surface generated by the rotation of the rotor, and that Whilein such suspended condition above the rotor and in the casing hopper, itis subjected to the reducing action of the radially disposed arms on therotor. This method and this machine differs from the usual type ofmachine, in which it is proposed to reduce the material by subjecting itto a crushing action under hammer blows, as it is fed into a wedgeshaped space between the reducing elements and an opposed wall. Vith thepresent construction, and in accordance with the method here disclosed,the reducing action takes place 'above the rotor, or equivalent element,and the relation of the rotor and casing and the construction of therotor is such that large fragments of material are retained in thecasing above the rotor until sufiiciently reduced to pass downwardlybetween the discs and arms of the skeleton rotor, so that practicallynone of the material, except that which has been first reduced to theproper size, can reach the screen below the rotor. The small percentageof oversize material which passes to the screen will be readily reduced,so that it will screen out as the final product by the action of thereducing elements which, it will be noted, have a path of travel closeto the screen element.

Such variations from the construction here shown as are merelymechanical may be made, and equivalent expedients for those. used forillustrative purposes here may be adopted without departing from therange of my invention.

I claim:

1. In a machine of the class described, the combination of a rotor; aplurality of radially extending, rigid, reducing elementscircun'iferentially disposed and spirally arranged longitudinally ofsaid rotor and which, when the rotor is in motion, generate asubstantially continuous revolving materialsupporting surface; and ahopper for the material to be reduced arranged above and closelyembracing at its lower end said rotor to retain the n'iaterial infloating condition on said rotor and to prevent oversize materialpassing between said rotor and the lower end of said hopper.

A rotor for a machine of the class described having a skeleton frame topermit the passage of reduced material through the rotor; and aplurality of radially extending, ircumferentially disposed, and spirallyarranged reducing elements extending from said skeleton frame.

3. In a machine of the class described, a skeleton rotor includingsubstantially radially extending reducing members rigidly mounted inspaced relation to each other, and means for laterally and positivelyconfining fragments above a desired maximum size of a fed mass of lumpmaterial to a top zone of the rotor periphery, whereby, the rotor beingin rotation the fragn'lents of substantially the desired maximum sizeand under may fall immediately through the rotor or pass beyond saidconfining means, while fragments above the desired maximum size will befloated on said reducing members within said top zone until reduced tosubstantially the desired maximum size.

at. In a machine of the class described, a rotor comprising a skeletonframe made up of a plurality of disc'like members spaced from each otheralong the rotor axis, a plurality of rod-like fastening means extendingthrough said discs, a plurality of substantially radially extendingreducing members rigidly mounted on said rod-like fastening meansbetween said disc-like members, and means for laterally and positivelyconfining fragments above a desired maximum size of a fed mass of lumpmaterial to a top zone of the rotor periphery, whereby, the rotor beingin rotation, the fragments of substantially the desired maximum size andunder may fall immediately through the rotor or pass beyond saidconfining means, while fragments above the desired maximum size will befloated on said reducing members within said top zone until reduced tosubstantially the desired maximum size.

5. In a machine of the class described, a rotor comprising a skeletonframe made up of a plurality of disc-like members spaced from each otheralong the rotor axis, a plurality of rod-like fastening means extendingthrough said discs, a plurality of substantially radially extendingreducing members rigidly mounted on said rod-like fastening meansbetween said disc-like members, the adjacent reducing members axially ofthe rotor being spaced by a distance greater than the distance betweenthe outer sides of adjacent disc-like nwmbcrs. and means for laterallyand positively confining fragments above a desired maximum size of a.fed mass of lump material to a top zone of the rotor, preferably,whereby the rotor being in rotation, the fragments of substantially thedesired maximum size and under may fall immediately through the rotor orpass beyond said confining means, While fragments above the desiredmaximum size will be floated on said reducing members Within said topzone until reduced to substantially the desired maximum size.

In testimony whereof I have hereunto set my hand.

WILLIAM K. LIGGETT.

